Many marijuana users find that shortly after toking up they start to feel very hungry. While researchers have been trying to find the root of the problem for years, a recent study has established what they believe to be the answer, in a bunch of neurons which they thought were responsible for feelings of satiety. These neurons, known as the POMC neurons are located in the hypothalamus, the region which is usually associated with such instincts as feeding, alertness and sexual arousal, and which normally sends chemical signals to tell the brain to stop eating.
In previous studies where scientists have shut down POMC neurons in mice, all the rodents became very overweight. During the most recent study carried out by Tamas Horvath at the Yale School of Medicine, it was suggested that compounds known as cannabinoids which are contained in marijuana might be impeding the POMC neurons’ activity. However, during their research they discovered that this wasn’t the case at all, as when they injected these cannabinoids into the rodents, it actually turned off adjacent cells that normally slow down the activity in the POMC neurons. This meant that the activity in the neurons increased, while the cannabinoids simultaneously caused the POMC neuron to release endorphins, which are known to cause increased appetite. Of course, this had a double effect on the appetite, meaning that even if a pot smoker had just eaten, smoking marijuana caused the neurons that normally indicate satiety, to actually tell them that they were hungry.
While this study may give an insight into why marijuana smokers get the munchies, it has to be remembered that the study was carried out with mice, not with humans. However, the hypothalamus and neural circuits of mice and humans work in pretty much the same way, and while we can’t be 100% certain that it’s the case, it’s a reasonable assumption to make. Plus, this study should not be taken in isolation, as only last year, researchers found that cannabinoids also had an effect on the olfactory centre, making mice much more sensitive to smells, with other previous studies indicating that cannabinoids also had the ability to increase the level of dopamine in the brain, the stuff that gives us the feel good factor when we eat.